A tray column in the related art uses a tray floor as a basic member for gas-liquid contact, on which the gas phase and the liquid phase flow in an intersecting way. The gas phase and the liquid phase in the tray column flow reversely in series, and the liquid phase enters into the downcomer by overflow and then falls onto the liquid receiving pan of a lower tray. The tray can be classified into two types according to a flow direction of the liquid on the tray floor. The first type of tray is called an overflow tray, in which the flow directions of the liquids on the tray floors are parallel on the whole and the flow distances of the liquids on the tray floors are approximately the same. The second type of tray is called a multiple downcomer tray, such as the ADV-MP tray (U.S. Pat. No. 6,746,003 and Chinese Patent No. 1878601A), the Hi-Fi tray (U.S. Pat. No. 6,824,750 and Chinese Patent No. 1400918A), the MD tray (U.S. Pat. No. 3,410,540), the ECMD tray and so on. The flow of the liquid on the tray floor of the multiple downcomer tray is a diffusion flow, a contraction flow or a combined flow of both.
Compared with the overflow tray, the multiple downcomer tray has a greater liquid treatment capacity, and can overcome the problem of bias flow of the overflow tray. However, the flow of the liquid on the tray floor of the multiple downcomer tray is inhomogeneous and is the combined flow of the diffusion flow and the contraction flow (such as for the Hi-Fi tray, the MD tray and the ECMD tray) or the pure diffusion flow (such as for the ADV-MP tray). The flow directions of the liquids on the tray floors are not consistent and the flow distances of the liquids on the tray floors are not the same, and thus the liquid-gas ratios on the tray floors are not the same, which influences the tray efficiency of the multiple downcomer tray.